Warewasher with intermediate blowoff zone or cycle step

ABSTRACT

A warewash machine for washing wares includes a housing defining a chamber for receiving wares, the chamber having an inlet end, an outlet end, multiple liquid spray zones between the inlet end and the outlet end, and a conveyor for moving wares along a conveyance path through the multiple liquid spray zones in a ware travel direction, the multiple liquid spray zones including a main wash zone and a final rinse zone. An intermediate zone is located, relative to the ware travel direction, after the main wash zone and before the final rinse zone. The intermediate zone includes a blowoff system including multiple blowoff nozzles that direct non-liquid flows onto wares to move residual detergent solution and soils from the wares as the wares move through the intermediate zone. A batch-type machine could also be provided with an intermediate non-liquid blowoff step.

TECHNICAL FIELD

This application relates generally to warewashers such as those used incommercial applications such as cafeterias and restaurants and, moreparticularly, to systems and methods to utilize air and/or steam toenhance cleaning via a blowoff operation.

BACKGROUND

Commercial warewashers commonly include a housing which defines one ormore internal washing and rinsing zones for dishes, pots pans and otherwares. In conveyor-type machines wares are moved through multipledifferent spray zones within the housing for cleaning (e.g., ASR(automatic soil removal), pre-wash, wash, post-wash (aka power rinse)and rinse zones). One or more of the zones include a tank in whichliquid to be sprayed on wares is heated in order to achieve desiredcleaning. In batch-type machines wares are typically manually moved intoa generally stationary location within a chamber for cleaning (includingwash and rinse steps), and then manually removed from the machine uponcompletion of all operations/steps of the cleaning cycle.

Reduced water consumption is becoming more important in certain areas inview of the growing demands for water as well as an increase in thenumber of drought stricken areas.

The cleanliness of dirty wares through a warewash machine is affected byseveral factors and includes under-dosing or over-dosing of detergentthat could lead to imbalance in food soil load to detergent ratio in thewash solution. Both situations, under-dosing or over-dosing leads topoor wash quality. Under-dosing leads to possible food soils on wareswhile over-dosing leads to wares with high levels of residual detergentfrom the wash solution. Achieving the right balance between thedetergent dose and food soil load comes with its own challenges becausethe water types and ware material should be considered.

Moreover, washing of wares with pulps from tomatoes and/or orange if notprescrapped effectively leads to some form of re-deposition. In thepast, use of large amounts of water for washing and rinsing dealt withsome of these issues. However, today given the lower water use needs,this presents challenges.

It would be desirable to provide a warewasher system and method thatenhances cleaning even in machines with reduced water consumption.

SUMMARY

A solution to the aforementioned issues is provided by an intermediateblowoff zone or cycle step that results in blowing off residual washsolution and/or food soil from wares.

In one aspect, a warewash machine for washing wares includes a housingdefining a chamber for receiving wares, the chamber having an inlet end,an outlet end, multiple liquid spray zones between the inlet end and theoutlet end, and a conveyor for moving wares along a conveyance paththrough the multiple liquid spray zones in a ware travel direction, themultiple liquid spray zones including a main wash zone and a final rinsezone. An intermediate zone is located, relative to the ware traveldirection, after the main wash zone and before the final rinse zone. Theintermediate zone includes a blowoff system including multiple blowoffnozzles that direct non-liquid flows onto wares to move residualdetergent solution and soils from the wares as the wares move throughthe intermediate zone.

In another aspect, a warewash machine includes a housing defining achamber for receiving wares, the chamber accessible by a door that ismovable between open and closed positions relative to a chamber accessopening. A wash spray system is provided in the chamber for sprayingwash liquid from multiple wash nozzles. A rinse spray system is providedin the chamber for spraying rinse liquid from multiple rinse nozzles. Ablowoff system is provided in the chamber for delivering non-liquidflows from multiple blowoff nozzles toward wares in the chamber. Acontroller is configured to selectively run at least one cleaning cyclethat includes a washing step involving wash liquid sprays from the washnozzles, a rinsing step involving rinse liquid sprays from the rinsenozzles and an intermediate blowoff step involving non-liquid flows fromthe blowoff nozzles, wherein at least part of the intermediate blowoffstep occurs after the washing step has concluded and before the rinsingstep has started.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevation of one embodiment of a warewasherincorporating an intermediate blowoff zone;

FIG. 2 is schematic side elevation of one embodiment of an intermediateblowoff zone;

FIG. 3 is schematic side elevation of another embodiment of anintermediate blowoff zone;

FIG. 4 is schematic side elevation of another embodiment of anintermediate blowoff zone;

FIG. 5 is schematic side elevation of another embodiment of anintermediate blowoff zone;

FIG. 6 is a schematic top plan view of a conveyor machine including twointermediate blowoff zones; and

FIG. 7 is a schematic side elevation of a batch-type machine with ablowoff system.

DETAILED DESCRIPTION

FIG. 1 shows a warewash machine 10 of the conveyor-type. The machineincludes a housing 12 defining an internal chamber 14 for receivingwares 90 for the purpose of cleaning. The chamber has an inlet end 16,an outlet end 18 and multiple liquid spray zones 20A-20D between theinlet end 16 and the outlet end 18. A conveyor 22 moves wares along aconveyance path 24 through the multiple liquid spray zones in a waretravel direction 26. Various of types of conveyors may be used,including continuous conveyors or reciprocating jog type conveyors thatmove ware racks through the chamber in a series of intermittent steps.Infeed area 30 for ware staging and outfeed area 32 for receivingexiting wares are also provided.

Here, the multiple liquid spray zones include a pre-wash zone 20A, amain wash zone 20B, a dual rinse zone 20C and a final rinse zone 20D.Pre-wash zone 20A includes sets of upper 26A and lower 28A spray armswith spray nozzles, where a pre-wash liquid is delivered to the arms 26Aand 28A from a collection tank 34A via a pump (not shown) in arecirculating manner. Likewise, main wash zone 20B includes sets ofupper 26B and lower 28B spray arms with spray nozzles, where a washliquid is delivered to the arms 26B and 28B from a collection tank 34Bvia a pump (not shown) in a recirculating manner. Dual rinse zone 20Cincludes an upper 26C and lower 28C spray arm with spray nozzles, wherea rinse liquid is delivered to the arms 26C and 28C from a collectiontank 34C via a pump (not shown) in a recirculating manner. One or moreof the collection tanks 34A-34C may include a heating element formaintaining desired liquid temperatures. Final rinse zone 20D includesupper 26D and lower 28D spray arms with spray nozzles, where fresh hotrinse liquid is delivered to the arms via a pump (not shown) or linepressure from, for example, a booster heater (not shown) of the machine.A drying zone 40 with an associated blower 42 is located after the finalrinse zone, but machines without drying zones are also possible.

As indicated above, variations in the number of liquid spray zones isalso possible in such machines. The zones may be demarcated from eachother via hanging curtain structures 38 as shown, which curtainstructures help avoid excess overspray from one zone into anyimmediately adjacent zones.

Notably, an intermediate zone 50 is located, relative to the ware traveldirection 26, after the main wash zone 20B and before the final rinsezone 20D. Here, the intermediate zone 50 is located immediately afterthe main wash zone 20B and immediately before the dual rinse zone 20C,but variations are possible as will be described in further detailbelow. The intermediate zone includes a blowoff system includingmultiple blowoff nozzles that direct non-liquid flows onto wares to moveresidual detergent solution and soils from the wares as the wares movethrough the intermediate zone. The blowoff nozzles may output streams ofone or more of compressed air, steam or blower dryer air onto the waresas the wares move through the intermediate zone. Thus, no liquid spraysoccur in the intermediate blowoff zone 50.

Referring to FIG. 2, one arrangement of a blowoff system 52 inintermediate zone 50 is shown, where the system 52 includes overheadarms or manifolds 54A and 54B extending across the conveyance pathtransverse to the ware travel direction 26. The manifolds 54A and 54Binclude blowoff nozzles oriented to direct streams 56A and 56B onto thewares as shown, in a primarily downward direction (here with no upwardcomponents to the flows). The streams may be, for example, steam that isejected from the nozzles under pressure, or compressed air that is alsoejected under pressure. The steam could be supplied to the manifoldsfrom an on-site steam supply, where the machine includes a steam inletconnection for such purpose. An in-machine steam generator could also beprovided. Likewise, the compressed air could be supplied to themanifolds from an on-site compressed air supply, where the machineincludes a compressed air inlet connection for such purpose, or anin-machine air compressor could also be provided. The streams 56A and56B move residual detergent solution and soils from the wares in theintermediate zone, which fall downward onto a collection pan structure58, which is oriented and/or configured to direct the solution and soilsback into the wash tank 34B so that the solution and soils are notcarried over into the next liquid spray zone (here the dual rinse zone20C).

FIG. 3 shows another embodiment of a blowoff system 62 in theintermediate zone 50, where the system 62 includes side-located arms ormanifolds 64A and 64B at opposite sides of the conveyance path. Themanifolds 64A and 64B include blowoff nozzles oriented to direct streams66A and 66B onto the wares as shown. The streams may be, for example,steam that is ejected from the nozzles under pressure, or compressed airthat is also ejected under pressure, as noted above.

In either system 52 or 62, the number, position and orientation of themanifolds and nozzles can be adjusted as desired to improve on coverage.The nozzles may sweep the ware surfaces (leading and trailing sides) ofresidual food soil and/or wash solution down to the flow back pan 58,which drains to the wash tank 34A. By way of example, the intermediatezone 50 may include a total non-liquid flow from the blowoff nozzles ofbetween about 500 CFM and about 3500 CFM to achieve desired blowoff ofresiduals from the wares.

FIG. 4 shows another embodiment of a blowoff system 72 in theintermediate zone 50, where the system includes a blower 74 that feedsair to overhead outlet nozzles 76A and 76B that are oriented to directair streams 78A and 78B onto the wares as shown, in a primarily downwarddirection (here with no upward components to the flows). The blower 74may include a heating element to heat the air prior to ejecting thestreams 78A and 78B.

FIG. 5 shows a compressed air system arrangement where the temperatureof the compressed air entering the machine via compressed air input 80is heated via heating element 82 to a predefined temperature T2 to amaintain desired heat conditions in the machine. In the case of steamflows such heating is not necessary.

It is recognized that in a conveyor machine the location of theintermediate blowoff zone can vary. For example, the intermediate zone50 may be located any one of (i) immediately after the main wash zone20B and immediately before the dual rinse zone 20C as shown, (ii)immediately after the dual rinse zone 20C and immediately before thefinal rinse zone 20D, (iii) immediately after the main wash zone 20B andimmediately before the final rinse zone 20D (where there is no dualrinse between the two zones), (iv) immediately after the main wash zone20B and immediately before a power rinse zone (where the power rinseprecedes the final rinse and the dual rinse zone), (v) immediately afterthe power rinse zone and immediately before the dual rinse zone 20C.

Moreover, in some embodiments more than one intermediate blowoff zonemay be provided. For example, FIG. 6 schematically depicts an embodimentin which a first intermediate blowoff zone 50-1 is located immediatelyafter the main wash zone 20B and immediately before the dual rinse zone20C, and a second intermediate blowoff zone 50-2 is located immediatelyafter the dual rinse zone 20C and before the final rinse zone 20D.

In an exemplary operation in the case of conveyor type machine 10, thenon-liquid flows in the intermediate zone 50 could be activated by amachine controller 100, which selectively turns the non-liquid flowsfrom the blowoff nozzles ON in response to a predefined machinecondition. The turn on could be by opening a valve or starting a blowerdepending upon the blowoff system configuration. For example, thepredefined machine condition may be one of (i) initiation of conveyormovement, (ii) a specified time lapse after initiation of conveyormovement, (iii) triggering of a sensor 92 that detects wares in orentering the machine, (iv) triggering of a sensor 94 that detects waresin or entering the intermediate zone, (v) a specified time lapse after asensor 92 detects wares in or entering the machine, or (vi) a specifiedtime lapse after a sensor 94 detects wares in or entering theintermediate zone. Other predefined machine conditions could also act asthe trigger.

Referring now to FIG. 7, an exemplary batch-type machine 110 is shownand includes a housing 112 defining a chamber 114 for receiving wares.The chamber 114 accessible by a door 116 that is movable between openand closed positions relative to a chamber access opening 118. A washspray system 120 is provided in the chamber for spraying wash liquidfrom multiple wash nozzles, and may include wash arms 124, a collectiontank or sump 126 and a pump 128. A rinse spray system 130 is provided inthe chamber for spraying rinse liquid from multiple rinse nozzles, andmay include rinse arms 132 and a hot water booster 134. A blowoff system140 is provided in the chamber for delivering non-liquid flows frommultiple blowoff nozzles toward wares in the chamber, and may includeone or more arms or manifolds 142 with blowoff nozzles to directnon-liquid flow streams 144 onto the wares. A machine controller 150 isconfigured to selectively run at least one cleaning cycle that includesa washing step involving wash liquid sprays from the wash nozzles, arinsing step involving rinse liquid sprays from the rinse nozzles and anintermediate blowoff step involving non-liquid flows from the blowoffnozzles, where at least part of the intermediate blowoff step occursafter the washing step has concluded and before the rinsing step hasstarted. Preferably, all non-liquid flows from the blowoff nozzlesduring the intermediate blowoff step occur after the washing step hasconcluded and before the rinsing step has started. The blowoff nozzlesoutput streams of one or more of compressed air, steam or blower dryerair, as discussed above.

In an exemplary operation of the machine 110, the compressed air, steamor a blower dryer could be activated by the controller 150 according toa predefined machine condition, such as any of the following: (i)stopping of the wash pump 128, (ii) draining of the sump at theconclusion of a wash step of the cycle, (iii) a set time period afterend of the wash step of the cleaning cycles or (iv) a set time periodbefore beginning a rinse step of the cleaning cycle.

As used herein, the term controller is intended to broadly encompass anycircuit (e.g., solid state, application specific integrated circuit(ASIC), an electronic circuit, a combinational logic circuit, a fieldprogrammable gate array (FPGA)), processor(s) (e.g., shared, dedicated,or group—including hardware or software that executes code), software,firmware and/or other components, or a combination of some or all of theabove, that carries out the control functions of the machine or thecontrol functions of any component thereof.

Use of such sheeting zones in flow through machines or sheetingoperations as part of the cleaning cycle in a batch type machine mayprovide advantages including: saving wash solution, make up waterdetergent and fills, leading to improved ware wash by removing orreducing residual detergent and/or food soil on wares, enhancedperformance of the dual rinse, power rinse and/or the final rinse,improvement of HUEs (heat equivalent units) transferred to the wares ifsteam, heated compressed air, steam or blower dryer system is used,reduction of the frequency of changing the dual rinse and/or power rinsetanks, and/or improved drying.

It is to be clearly understood that the above description is intended byway of illustration and example only and is not intended to be taken byway of limitation, and that changes and modifications are possible.Accordingly, other embodiments are contemplated and modifications andchanges could be made without departing from the scope of thisapplication.

What is claimed is:
 1. A warewash machine for washing wares, comprising:a housing with a chamber for receiving wares, the chamber having aninlet end, an outlet end, multiple liquid spray zones between the inletend and the outlet end, and a conveyor for moving wares along aconveyance path through the multiple liquid spray zones in a ware traveldirection, the multiple liquid spray zones including a main wash zoneand a final rinse zone; an intermediate zone located, relative to theware travel direction, after the main wash zone and before the finalrinse zone, where the intermediate zone includes a blowoff systemincluding multiple blowoff nozzles that direct non-liquid flows ontowares to move residual detergent solution and soils from the wares asthe wares move through the intermediate zone.
 2. The warewash machine ofclaim 1 wherein the blowoff nozzles output streams of one or more ofcompressed air, steam or blower dryer air onto the wares as the waresmove through the intermediate zone.
 3. The warewash machine of claim 1wherein the blowoff system includes (i) a compressed air input or deviceto provide compressed air to the blowoff nozzles or (ii) a steam inputor steam generator to provide steam to the blowoff nozzles.
 4. Thewarewash machine of claim 1 wherein the intermediate zone does notinclude any liquid sprays.
 5. The warewash machine of claim 4 wherein afirst spray blocking curtain is positioned at an upstream end of theintermediate zone and a second spray blocking curtain is positioned as adownstream end of the intermediate zone.
 6. The warewash machine ofclaim 1 wherein the intermediate zone includes a flowback pan structureto direct falling residual detergent solution and soils into acollection tank upstream of the intermediate zone in the ware traveldirection.
 7. The warewash machine of claim 1 wherein the intermediatezone is located one of (i) immediately after the main wash zone andimmediately before a dual rinse zone, (ii) immediately after a dualrinse zone and immediately before the final rinse zone, (iii)immediately after the main wash zone and immediately before the finalrinse zone, (iv) immediately after the main wash zone and immediatelybefore a power rinse zone, (v) immediately after a power rinse zone andimmediately before a dual rinse zone.
 8. The warewash machine of claim 1wherein a power rinse zone or dual rinse zone is located between themain wash zone and final rinse zone, wherein the intermediate zone isafter the main wash zone and before the power rinse zone or the dualrinse zone, and a second intermediate zone with non-liquid blowoff islocated after the power rinse zone or the dual rinse zone and before thefinal rinse zone.
 9. The warewash machine of claim 1 wherein theintermediate zone includes a total non-liquid flow from the blowoffnozzles of between about 500 CFM and about 3500 CFM.
 10. The warewashmachine of claim 1 wherein the intermediate zone includes first blowoffnozzles that direct non-liquid flows onto leading sides of wares andsecond blowoff nozzles that direct non-liquid flows onto trailing sidesof wares.
 11. The warewash machine of claim 1, further comprising acontroller that selectively turns the non-liquid flows from the blowoffnozzles ON in response to a predefined machine condition.
 12. Thewarewash machine of claim 11 wherein the predefined machine condition isone of (i) initiation of conveyor movement, (ii) a specified time lapseafter initiation of conveyor movement, (iii) triggering of a sensor thatdetects wares in or entering the machine, (iv) triggering of a sensorthat detects wares in or entering the intermediate zone, (v) a specifiedtime lapse after a sensor detects wares in or entering the machine, or(vi) a specified time lapse after a sensor detects wares in or enteringthe intermediate zone.
 13. The warewash machine of claim 1 wherein allnon-liquid flows are downward.
 14. A warewash machine for washing wares,comprising: a housing with a chamber for receiving wares, the chamberaccessible by a door that is movable between open and closed positionsrelative to a chamber access opening, a wash spray system in the chamberfor spraying wash liquid from multiple wash nozzles, a rinse spraysystem in the chamber for spraying rinse liquid from multiple rinsenozzles, and a blowoff system in the chamber for delivering non-liquidflows from multiple blowoff nozzles toward wares in the chamber, whereina controller is configured to selectively run at least one cleaningcycle that includes a washing step involving wash liquid sprays from thewash nozzles, a rinsing step involving rinse liquid sprays from therinse nozzles and an intermediate blowoff step involving non-liquidflows from the blowoff nozzles, wherein at least part of theintermediate blowoff step occurs after the washing step has concludedand before the rinsing step has started.
 15. The warewash machine ofclaim 14 wherein the blowoff nozzles output streams of one or more ofcompressed air, steam or blower dryer air.
 16. The warewash machine ofclaim 14 wherein all non-liquid flows from the blowoff nozzles duringthe intermediate blowoff step occur after the washing step has concludedand before the rinsing step has started.